How do you make a rounded triangle of "X" height?

Hi all,
My maths is not so hot.
I have a routine that produced a rounded cube of length x width x height, with radius as the rounded edges,

What I really want is to produce a rounded triange of sqrt(length*length+width*width) as the two sides with a height of X

Any ideas?

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appjaws - Core XYUV Duet Ethernet Duex5
firmware 3.1.1 Web Interface 3.1.1
Ormerod 1-converted to laser engraver, Duet wifi
OpenSCAD version 2020.07
slic3r-1.3.0, Simplify3D 4.1.2, Cura-4.4.1

draw a cylinder of the desired radius and height at each vertex location, and put a hull around the entire thing. You might need to use a little trig/geometry to move the cylinders towards the interior of the triangle by the radius if you want the cylinders to be totally within the triangle; otherwise each cylinder, and thus the hull, will overhang the triangle by the amount of the radius.

@jbernardis , Thank you, that is just what I wanted, it's so easy when you know how!!!

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appjaws - Core XYUV Duet Ethernet Duex5
firmware 3.1.1 Web Interface 3.1.1
Ormerod 1-converted to laser engraver, Duet wifi
OpenSCAD version 2020.07
slic3r-1.3.0, Simplify3D 4.1.2, Cura-4.4.1

If you want the corners of the prism rounded as well, put a sphere at each vertex location instead of a cylinder.
If you want it hollow (a framework) put the spheres/cylinders in pairs with separate hull functions for each pair.

Dave